Combined motor and relay timing device



Sph 'L 195 R. s. LUNDIN COMBINED MOTOR AND RELAY TIMING DEVICE Filed Aug. 24, 1962 United States Patent O 3,205,379 COMBINED MOTOR AND RELAY TIMING DEVICE Robert S. Lundin, Thomaston, Conn., assignor to General Time Corporation, New York, N.Y., a corporation ot Delaware Filed Ang. 24, 1962, Ser. No. 219,290 6 Claims. (Cl. 307-141) The present invention relates to timers and more particularly to a time delay device having a synchronous A.C. timing motor.

A common type of timing device employs an A.C. motor driving a cam switch, with the cam switch serving to control a relay or contactor feeding current to a load. It is t-he object of the present invention to provide a time delay device in which the usual cam switch interposed between the motor and the relay is eliminated and which may, therefore, be constructed at minimum cost. It is another object to provide a time delay switch of the motor driven type having a high degree of accuracy and reliability.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIGURE l is a face view of a timer constructed in accordance with the present invention.

FIG. 2 is a side view of the timer of FIG. 1.

FIG. 3 is a vertical section taken through the motor and associated gear housing.

FIG. 4 is a circuit diagram of the timer.

FIGS. 5 and 6 are stop motion views of the relay contacts showing the switching which takes place during a typical timing cycle.

FIG. 7 is a fragmentary view showing the reference position of the cam in an alternate, non-clutching embodiment.

While the invention has been described herein in connection with .a preferred embodiment, it will be understood that I do not intend to be limited to the disclosed embodiment but intend to cover the various equivalent and alternative constructions included within the spirit and scope of the appended claims.

Turning now to the drawing, a timer constructed in accordance with the present invention includes a sheet metal frame 10 mounting a relay 1I and motor unit 17. The relay is of familiar commercial design having a magnetic frame encircled by a -coil I6 for operating a rockable armature 17. The latter is kept open by restoring spring 18. Since the relay is intended for operation on A.C., it includes a shading ring 19.

Arranged above the armature and mounted upon the relay frame is a Contact assembly carrying stationary contact blades 21, 22 and a central contact blade 23, the latter being connected to the armature 17 by means of a yoke 24. As will appear, such contact blades are ernployed for control purposes. Arranged alongside on the relay frame is `a second set of contact blades 25, 26, 27 which may be of identical construction for the purpose of controlling current flow to a connected load.

In accordance with the present invention a cam is provided on the motor output shaft for directly acting upon the relay contacts for the purpose of producing closure of the relay following a predetermined time delay and hence control of the current supplied to the connected load. More specifically, in accordance with the present invention the relay is provided with a normally open contact which is interposed between the relay coil Iand the supply line, a normally closed contact which is interposed between the motor and the supply line, and a cam follower arranged in the path of movement of the motor driven cam for initiating closure of the normally open contact s 3,205,379 Patented Sept. A7, 1965 and hence closure of the relay accompanied by automatic turn-off of the motor. Thus a cam 30 is provided in the form of an .arm having a tapered cam surface 31 `at its end mounted on a shaft 32 which forms the output shaft of the motor unit. Mounted upon the blade 21 of the relay in the path of movement of the cam is a cam follower 35. Referring to the schematic diagram, FIG. 4, it will be noted that the timer is supplied from the regular A.C. supply lines L1 and L2. The motor 12, as shown, is connected to the supply lines via normally closed contact blades 21, 23, while the Winding of the relay is connected to the lines via the normally opening contact blades 22, 23. The load is fed from the line via normally open contacts 25, 27. To initiate operation of the timer a line switch 38 is connected in series with the line L1. It will be apparent, then, with the cam 30 in initial reference position closure of the line switch 38 causes rotation of the motor, thereby driving the cam into engagement with the cam follower 35. The downward force exerted by the cam upon the stack causes contact between the blades 22, 23 of the relay which perform a sealing function. The relay thereupon closes which seats the sealing contacts firmly together and which draws the contact blade 23 away from the contact blade 21 thereby breaking the motor circuit and terminating rotation of the motor. The closure of the load contacts 25, 27 on the relay, which occurs at the same time, completes the circuit to the load.

It is one of the features of the present inventive com bination that means are provided for restoring the cam 30 to reference position immediately upon deenergization of the motor. To accomplish this, the motor unit 12 includes an automatic clutch which is engaged whenever the motor is energized and which is disengaged at all other times, and the cam is provided with a stop and return spring for biasing the cam against the stop to define a precise reference, ior starting, position. In order to understand the nature of the automatic clutching arrangement, reference is made to prior Schellens Patent 2,334,040, the main features of which lare embodied in FIG. 3 of the present drawings. In this figure it will be noted that the motor unit includes a magnetic frame 40 encircled by a winding 41 which cooperates with a rotor 42. The shaft carries .a pini-on 44 at its inner end rarranged for meshing with a first gear 45. Only a portion of the stepdown gear train is shown, terminating in gears 46, 47. As shown, the shaft 43 of the rotor is mounted for endwise movement between a dropped out position indicated by the dot- .dash lines in which the rotor pinion 44 is disengaged from the gear 45 and `an energized o r sucked in position in which the rotor pinion meshes with the gear 45 for transfer or torque through the gear train to the output shaft. In order to insure that the rotor is disengaged when current is not flowing through the motor, a leaf spring 48 is provided which exerts endwise pressure upon the rotor shaft. For the purpose of establishing a reference or starting position, the output shaft 32 of the motor carrie-s a stop member 50 which cooperates with a stop 51 in the form of a small bracket on the frame of the device. A coil spring 52 is anchored to the frame at 53 and is connected at its other end to the shaft 32 so that the shaft tends to be urged in a direction to bottom -on the sop 51. In order to vary the time interval, ie., the arc traversed by the cam from the reference position to the switch operating, the cam 30 is rotatably adjustable and is held in adjusted position by means of a nut 55 or the like. To facilitate setting of the time interval, the cam 30 `carries a pointer 56 which cooperates with a suitable scale on the periphery of the stop member 50, the latter being preferably of disc shape.

In the operation of the preferred form of the device the cam 30 is adjusted by temporarily loosening and retightening the nut 55 which secures it to the shaft. Clo- 1against one of the contact blades of the relay.

s Sure of the line switch 33 energizes the winding of the motor 12 which simultaneously sucks in the rotor to complete the drive train and causes rotation of the output shaft 32 at a slow timed rate. After expiration of the predetermined time interval, the cam 30 engages the cam follower 3S on the relay blade 21, compressing the stack and completing the circuit between blades 22, 23 (FIG. 5). This energizes the relay winding causing closure of armature 17, which, acting through yoke 24, lcauses the blade 23 to be drawn downwardly. This seals in the circuit to the relay winding and immediately thereafter causes separation between the blades 21, 23 which opens the motor circuit (FIG. 6). The load may be normally off and turned on after the time delay or normally on and turned off after the time delay depending upon whether contacts 26, 27 or 25, 27 are used.

Upon deenergization of the motor, the rotor 42 drops out under the urging of the biasing means 48, thereby breaking the drive train. Consequently the return spring 52 is free to act, turning the output shaft 32 and the connected gearing backwards until the stop member 50 on the motor output shaft again seats against the stop 51. Since closure of contact blades 25, 27 feeding the load takes place simultaneously with closure of the sealing contacts 22, 23, and since the relay is sealed in, the load continues to be energized. When it is desired to turn off the load, the line switch 38 is opened. To initiate a new time delay cycle, the switch Sti is again closed, energizing the motor for rotation of the cam 30.

It is one of the features of the preferred embodiment discussed above that it is adjustable and produces a reliable, consistent time interval with immediate reset of the cam to a positively defined reference position. The result is acheived by direct action of the motor driven cam The timer is of inherently low cost since it avoids use of any separate cam control switch contacts for operating the relay. If desired, and where the adjustability feature is not important, the cost may be still further reduced by employing a motor unit 12 of the conventional, non-clutching type and by omission of the stop 51 and return spring 52. In accordance with one of the aspects of the invention the cam surface 31 and the cam follower 35 are shaped to provide abrupt drop-olf closely spaced to the point of operation of the switch contacts so that the momentum which is inherent in the motor is capable of causing the cam to overtravel beyond the cam follower into a reference position. When employing this alternate arrangement the cam must traverse 360 in each cycle and a motor unit is chosen in which the poles and gear ratio are such that the desired time delay corresponds to one full revolution. The reference position of the cam in such alternate embodiment and after completion of a timing cycle is shown in FIG. 7. l

The preferred cam shape is set forth in the drawings. However, it will be understood by one skilled in the art that the invention is not limited to the particular cam shape and consequently the term cam employed in the following claims shall be understood to cover any specific form of mechanical operator interposed between the motor shaft and the relay contacts capable of initiating the operation of the relay by mechanical engagement of the relay contacts.

I claim as my invention:

1. In a device for delaying application of current to a load circuit for a predetermined time interval, the combination comprising a relay having a normally open contact, a normally closed contact and a set of load contacts, a timing motor unit having an output shaft and including a clutch interposed between the motor and the output shaft which is so associated with the motor as to be engaged only when the motor is energized, the output shaft being driven when the clutch is engaged, a pair of supply lines, the normally closed contact and the motor being connected in series between the supply lines so that the motor is energized when the associated contact is closed, the normally open Contact and the relay being connected in series between the supply lines so that the relay is energized when the associated contact is closed, a cam on the output shaft cammingly associated with the relay contacts for closing the normally open contact and opening the normally closed contact following expiration of a predetermined time interval after motor energization whereby the relay is energized and the motor is deenergized, and means including a stop and a return biasing spring for causing the cam to be driven to and maintained in a reference position when the motor is deenergized.

2. In a timing device, the combination comprising a relay having a coil, an armature and a plurality of contacts controlled thereby, a pair of supply lines adapted to be connected to a source of current, a load, a timing motor unit having an output shaft, selected ones of the contacts and the load being connected in series between the supply lines so that the flow of current to the load is controlled by operation of the relay, the relay contacts including a normally closed contact connected in series with the motor between the supply lines and including a normally open contact connected in series with the relay coil between the supply lines, and a cam on the output shaft cammingly associated with the relay contacts for closing the normally open Contact and opening the normally closed contact upon engagement therewith following a predetermined time interval whereby the relay is energized and the motor is deenergized.

3. In a timing device, the combination comprising a pair of supply lines, a relay having a set of contacts including a normally open contact and load contacts, the normally open Contact being connected in series with the relay between the supply lines, a timing motor, a cam associated with the timing motor and mechanically coupled to the normally open contact for initiating energization of the relay following a predetermined time delay, and means rendered operative, concurrently with energization of the relay for turning off the motor.

4. In a timing device for delaying the switching of a load for a predetermined time interval, the combination comprising a pair of supply lines adapted to be connected to an alternating current source, an alternating current responsive relay having a set of load contacts and a relay control contact, the relay control contact being connected in series with the relay between the supply lines, an alternating current responsive timing motor having an output shaft, and a cam on the output shaft which normally occupies a reference position and is cammingly associated with the relay control contact for closing the relay control contact following timed movement of the cam from its reference position whereby the relay is energized.

5. In a synchronous timing device for switching a load after a predetermined time interval, the combination comprising a pair of supply lines, a relay having a coil, armature and stack of contact blades, the contact blades including a normally open Contact blade connected in series with the coil across the supply lines, a timing motor having an output shaft, a cam on the output shaft, a cam follower on the stack of contact blades positioned in the path of movement of the cam for producing closure of the normally open contact blade upon engagement by the cam so that the relay is energized causing the cam follower to be moved out of the path of movement of the cam whereby the cam clears the cam follower by reason of the momentum stored in the motor to condition the device for a subsequent operating cycle, and means for deenergizing the relay to institute a succeeding cycle.

6. In a timing device for securing a predetermined time delay, the combination comprising a pair of supply lines, a relay having a coil, armature and stack of three contact blades, the outer blades respectively carrying a normally open Contact and a normally closed contact and the central blade connected to the armature and carrying a Contact which cooperates with the normally open contact and the normally closed contact thereby to form a single pole double throw switch, the central blade Contact normally engaging the normally closed contact, an alternating current responsive timing motor having an output shaft, the normally closed Contact and the central blade Contact being connected in series with the motor between the supply lines, the normally open contact and the central blade contact being connected in series with the relay coil between the supply lines, a cam on the output shaft having a reference position, means for initiating rotation of the motor for driving the cam from the reference position, a cam follower on at least one of the Contact blades interposed in the path of movement of the cam so that the cam follower is engaged by the cam after a predetermined time interval whereby the central blade contact is moved out of engagement with the normally closed contact and into engagement with the normally open contact causing the relay to be energized and the motor to be deenergized, the cam follower being moved out of the path of movement of the cam upon energization of the relay and momentum of the motor being effective to cause overtravel of the cam beyond the cam follower to condition the device for a subsequent Operating cycle.

No references cited.

LLOYD MCCOLLUM, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

6. IN A TIMING DEVICE FOR SECURING A PREDETERMINED TIME DELAY, THE COMBINATION COMPRISING A PAIR OF SUPPLY LINES, A RELAY HAVINGA COIL, ARMATURE AND STACK OF THREE CONTACT BLADES, THE OUTER BLADES RESPECTIVELY CARRYING A NORMALLY OPEN CONTACT AND A NORMALLY CLOSED CONTACT AND THE CENTRAL BLADE CONNECTED TO THE AMRATURE ANDCARRYING A CONTACT WHICH COOPERATES WITH THE NORMALLY OPEN CONTACT AND THE NORMALLY CLOSED CONTACT THEREBY TO FORM A SINGLE POLE DOUBLE THROW SWITCH, THE CENTRAL BLADE CONTACT NORMALLY ENGAGING THE NORMALLY CLOSED CONTACT, AN ALTERNATING CURRENT RESPONSIVE TIMING MOTOR HAVING AN OUTPUT SHAFT, THE NORMALLY CLOSED CONTACT AND THE CENTRAL BLADE CONTACT BEING CONNECTED IN SERIES WITH THE MOTOR BETWEEN THE SUPPLY LINES, THE NORMALLY OPEN CONTACT AND THE CENTRAL BLADE CONTACT BEING CONNECTED IN SERIES WITH THE RELAY COIL BETWEEN THE SUPPLY LINES, A CAM ON THE OUTPUT SHAFT HAVING A REFERENCE POSITION, MEANS FOR INITIATING ROTIONA OF THE MOTOR FOR DRIVING THE CAM FROM THE REFERENCE POSITION, A CAM FOLLOWER ON AT LEAST ONE OF THE CONTACT BLADES INTERPOSED IN THE PATH OF MOVEMENT OF THE CAM SO THAT THE CAM FOLLOWER IS ENGAGED BY THE CAM AFTER A PREDETERMINED TIME INTERVAL WHEREBY THE CENTRAL BLADE CONTACT IS MOVED OUT OF ENGAGEMENT WITH THE NORMALLY CLOSED CONTACT AND INTO ENGAGEMENT WITH THE NORMALLY OPEN CONTACT CAUSING THE RELAY TO BE ENERGIZED AND THE MOTOR TO BE DEENERGIZED, THE CAM FOLOWER BEING MOVED OUT OF THE PATH OF MOVEMENT OF THE CAM UPON ENERGIZATION OF THE RELAY AND MEMONTUM OF THE MOTOR BEING EFFECTIVE TO CAUSE OVERTRAVEL OF THE CAM BEYOND THE CAM FOLLOWER TO CONDITION THE DEVICE FOR A SUBSEQUENT OPERATING CYCLE. 